Airplane control surface



June 11, 1946 NQYES, 2,401,790

' v AIRPLANE GONTROL' SURFACE Filed Jan. 19, 1944 s Sheets-Sheet 1 mill FIG. 2

INVENTORS JOHN NOYES JR.

ATTORNEY m v I g BY YRON 1. AGGETTJR. a Q I/ v 5 June 11, 1946- J. 'NOYES, JR., ETAL 2,401,790

AIRPLANE CONTROLSURFACE I Filed Jan. "19, 1944 5 She ets-Sheec 2 ATTORNEY June 11, 1946. J. NOYES, JR., ETAL 2,401,790 Y AIRPLANEVCON'IIRQL SURFACE Filed Jan. 19, 1944 3 Sheets-Sheet. 3

W v v 56 INVENTORS 4 JOHN NOYES JR.

m 9 ATTORNEY MYRON L. DAGVGETT JR.

Patented June ll, 1946 'UNITED STATES PATENT OFFICE University City,

assignors to Curtiss- Wright Corporation, a corporation of Delaware Application January 19, 1944, Serial No. 519,072

Claims. 1

This invention relates to airplane control surfaces of the type characterized by cooperating main and auxiliary airfoils, being concerned more particularly with a mechanism which is responsive to the movement of the main airfoil to effect a differential movement of the auxiliary airfoil, or airfoils.

One object of the invention is to provide a mechanism of the character generally described which may be adjusted, as occasion may require, to cause the auxiliary airfoil, or airfoils, to lag, lead, or move at the same rate as the main airfoil.

A further object is to provide a mechanism which is so designed that, within limits, the degree of relative movement between the main and auxiliary airfoils may, with respect to a predetermined movement of the main airfoil, be varied at will.

A still further object is to provide a mechanism which will permit the auxiliary airfoil, or airfoils, to be availed of for trimming purposes and which may be adjusted to effect automatically the desired relative movement between the main and auxiliary airfoils for any trim setting of the latter.

A still further object is to provide a mechanism which is adaptable for use in connection with a control surface so designed and mounted that it automatically seeks and, under normal condition of rectilinear flight, tends to remain in a neutral or balanced position with respect to the direction of air flow.

A still further object is a novel design and arrangement of the parts of the mechanism, whereby to obtain simplicity in construction and dependability in operation.

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is a perspective view, in phantom, of an airplane having a control surface wherein auxiliary airfoils are controlled by a differential mechanism embodying the features of the invention. a

Figure 2 is anenlarged sectional view through the housing of the trim gear of the auxiliary airfoils.

Figure 3 is a perspective view of the cooperating control mechanisms for the main and auxiliary airfoils.

Figure 4 is an enlarged perspective view of the control mechanism for the auxiliary airfoils.

Figures 5 through 9, inclusive, are similar sectional views through the control mechanism for the auxiliary airfoils; Figure 5 showing the relation of the parts when the main and auxiliary airfoils occupy neutral positions and the parts are adjusted so that the airfoils may be controlled without relative movement between them; Figure 6 showing the relation of the parts and the relation of the auxiliary airfoils when, without further adjustment, the main airfoil is moved from the neutral position to a positive angle of attack; Figure 7 showing the relation of the parts when the main and auxiliary airfoils occupy neutral positions and the parts of the control mechanism are adjusted so that the auxiliary airfoils will lag the main airfoil when the latter is moved; Figure 8 showing the relation of the parts and the relation of the auxiliary airfoils when, without further adjustment, the main airfoil is moved to a positive angle of attack; and Figure 9 showing the relation of the parts and the relation of the auxiliary airfoils when the main airfoil is moved to a positive angle of attack and the parts of the control mechanism are adjusted so that the auxiliary airfoils lead the main airfoil.

Figure 10 is a detail section taken along line Iii-l0 of Figure 5.

The invention is illustrated, by way of example, in connection with an airplane which forms the subject matter of the co-pending application of Carl W. Scott and Willis L. Wells, Serial No. 509,318, filed November 6, 1943, the said airplane, which is of the so-called pusher type, being sufliciently indicated for the purpose in view by a showing of the forward section and mid-section of the fuselage l5. A horizontal control surface, or nose elevator I6, is carried by the nose section of the fuselage and is mounted for pivotal movement about a spanwise axis I! which is located within the leading edge of the elevator. As the airplane is designed so that all of the lifting and stabilizing forces are produced by the main wing IS, the nose elevator will not normally be subjected to a load and may occupy a neutral position which it seeks automatically and in which it tends to remain. The principal function of the nose elevator when employed in connection with the airplane illustrated is to impart a high degree of maneuverability to the airplane by rendering it highly responsive to the control stick, the location of the elevator a substantial distance ahead of a main wing which produces all lifting and stabilizing forces contributing in a large measure to the attainment of the results sought. Auxiliary airfoils l9 and 20 are mounted at the trailing edge of the main airfoil, being connected to the latter so that they may be angularly adjusted.

The symmetrical halves of the nose elevator are connected for unisonous, angular movement about the axis I1, being supported at opposite sides of the fuselage by suitable bearings located wholly within the nose section. As illustrated, the nose elevator is connected to a control stick 2| and is adapted to be operated, as in a conventional airplane, by fore and aft movements of the control stick. To this end, the latter is 'connected by a link 22 to an arm 23 on a rock shaft 24. Cranks which are carried at the opposite ends of the latter are connected by parallel series of push-pull rods 25 to brackets 26 which are located within the fuselage and which are suitably secured to the elevator structure.

The auxiliary airfoils l9 and '20 are intended primarily for trimming purposes. For example, if the airplane is for any reason nose heavy, the auxiliary airfoils may be adjusted to increase the lifting force produced by the elevator. Likewise a tail-heavy condition may be compensated by an opposite setting of the auxiliary airfoils, The latter may be manually adjusted for the purpose described by a control device 21. which is connected by a cable 28 to a winding drum 29. A shaft 36 (Figure 2) which carries the drum 29 is mounted in a'housing 3| which is mounted upon a suitable support, the'said housingaccommodating a driving gear 32 which isfixed to the shaft 30 and driven gears 33 and 34 which mesh with'the driving gear. The driven gears are fixed to shafts 35 and 36, respectively, one of which is connected to the power-transmitting element of flexible cable 3'? and the other of which is connected to the power-transmitting element of a similar cable 38. The power-transmittingelements of the cables Hand 38 are connected to the driving members of gear actuators 39 (Figure 3), the driven members of said actuators constituting parts of links 40 and 4| and being operative to shorten and lengthen the said link in any suitable manner. The link 46 is connected at its forward end to a crank 42 on the outer end of a torque tube 43 and ,at its rearward end to a lever arm 44 on the auxiliar airfoil 20. The'link 4t similarly connects a crank 45 on a torque tube 46 toa lever arm '41 on the auxiliary airfoil l9, it being noted, as indicated in Figure 1, that the axes of the torque tubes 43 and 46 are in alignment and are coincident with the axis of the main airfoil of the elevator. When the torque tubes 43 and 46 are held against angular movement, the control device 2! may be adjusted to elevate or lower the auxiliary airfoils to give them any desired predetermined setting with respect to the main airfoil of the elevator. V

The invention also contemplates the use of the auxiliary airfoils of the nose elevator, apart from their use for trimming purposes, and independently of such function, for automatically increasing and decreasing the load upon the control stick as circumstances may require-this being accomplished by'a difierential mechanism which is automatically operative in response to the movement of the main airfoil to cause the auxiliary airfoils to'mov'e faster or slower than, or at the same rate as, the main airfoil of the elevator and thereby to lead or lag the main airfoil or accompany it without relative movement.

A differential mechanism for actuating the auxiliary airfoils in themanner described is indicated generally at 48 (Figures 3 and 4). The said mechanism, as illustrated, may be adjusted by a control device 49 to effect any desired movement of the auxiliary airfoils l9 and 20 with relation of 'a bracket 55 which is adapted to befmo upon a suitable -'station'ary support. The lower end of the shaft 52 is externally threaded as indicated at 56 (Figure 10) and screws into the upper end of an internally threaded connecting "rod 51, the lower end of the latter carrying a clevis 58 which isconneci'ed by a pin 59 to the upper end of a lever arm 60 (Figure 4). The said arm is mounted for rocking movement upon a transverse shaft 6| between inwardly converging portions of the flanges 54 of the bracket 55 and at its lower end is forked to provide legs 62 and 63. A pivot shaft 64 which is carried between the legs 62 and 63 is formed with extensions to which links 65 and 66 are pivotally connected. The upper end of the link 65 and the upper end of a companion link 61 are connected by ap'in 68, the lower end of the link 6? being connected to a crank 69 on the inner end of the torque tube 46. A rod 10 which is connected at one end to the pin 68 is connected at the opposite end to a pin "H which is mounted between the upper ends of a pair of arms 12. The-said arms are carried by a-bearing member 13 which is fixed to, and hence which is'mo'vable with, the elevator. Adjacent its inner end the torquetube 43 is formed with a journal 14 (Figure 3) which is accommodated in'the bearing'memb'er 13. In a like manner the upper end of the link 66 and a link 15 are connected by a 'pin 16, the lower end of the link 15 being connected to a crank '13 (Figure 3) which is carried by the inner end of the torque tube 43, while one end of a rod 18 is connected to'the pin '16 and the opposite end is connected to a'bearing'memb'er 19. The latter is similar to the bearing member 13 and is adapted to accommodate a journals!) which is formed at the inner en'd'of the torque tube 43. Adjacent their outer ends the torque tubes 43 and 46 are supported in bearings 8|, it being 'noted'in this connection that the brackets 26 'which'are carried by the elevator are formed'with openings through which the torque "tubes '4'3 and 46 pass and are also formed withsuita'ble openings for "bearing supports82 in which'the'inn'e'r ends of the torque tubes are supported "for angular movement.

From "the foregoing it will be apparent that any movement of the elevator in'response to: the

control stick is transmitted through the differential mechanism to the torque tubes 43am 46, the attendant movement of the auxiliary airfoils l9 and 26 being dependent'upon the setting of the said mechanism as predetermined by the cont'rol'device 49 and being independentofa'riy setting of the auxiliary airfoils which may have been made for trimming purposes. In'thi's connection it will be noted that the control device '49 maybe rotated in opposite directions to cause axial displacement of the connecting 'rod 51 in opposite directions. The lever arm 60 may thus be rock'e'd'upon its pivottovary the position of the shaft 64 and hence the position of the axis the differential mechanism is adjusted in the manner described so that the axis of the pivot shaft 64 is aligned, as illustrated in Figure 5, with the axis about which the main airfoil turns, the main airfoil being indicated in this and in the similar vieWs by a chord line 83 while the auxiliary airfoils are indicated by a common chord line 84. Under such conditions the connecting rod causes the links 65 and 61 to move as a unit about an axis which is coincident with the axis about which the main airfoil turns. Hence the auxiliary airfoils turn with the main airfoil without relative movement as shown in Figure 6.

The auxiliary airfoils may, if desired, be caused to lag the main airfoil. This may be accomplished by adjusting the control device 49 to move the pivot shaft 64 in the direction of the axis of the pivotal connection between the link 61 and crank 69, as indicated in Figure 7, the further the pivot shaft is moved in such direction the less will be the movement of the auxiliary airfoils with respect to a predetermined movement of the main airfoil. When the pivot shaft is moved in the direction indicated, its axis will be moved closer to the axis of the pivotal connection between the link 61 and the crank 69. Hence the angular movement of the torque tube 46, and therefore of the auxiliary airfoil l9 will, as indicated in Figure 8, be less than the angular movement of the main airfoil of the elevator, In other words, the torque tube Will be rotated at a slower rate than the main airfoil and hence the net angular displacement of the auxiliary airfoil will be less than that of the main airfoil. It is immaterial in which direction the main airfoil is moved by the control stick, the auxiliary airfoil will always lag behind it.

To cause the auxiliary airfoil to lead the main airfoil it is only necessary to adjust the differential control device 49 to move the pivot shaft 64 in the opposite direction so that its axis is located ahead of the axis of the main airfoil, as indicated in Figure 9. When the pivot shaft is moved to such a position and the main airfoil is moved, the links 65 and 61 will cause the auxiliary airfoil to lead the main airfoil in both up and down movements of the latter.

From the foregoing it Will be apparent that the auxiliary airfoils l9 and are controlled by similar linkages and that the said linkages are individually driven, one by the connecting rod 10 and the other by the connecting rod 18. The two auxiliary airfoils, therefore, are moved simultaneously, in the same direction and to the same degree by the differential mechanism. Referring to the linkage for the auxiliary airfoil I9, it will be noted that the connecting rod 10 is displaced for any movement of the main airfoil a distance corresponding to such movement. The links 65 and 61 transmit the movement of the connecting rod 10 through the crank 69 to the torque tube 46, and hence to the auxiliary airfoil l9, In transmitting such movement to the torque tube 46, the links 65 and 61 move as a unit, without substantial relative movement between them, about the pivot shaft 64. As the links 65 and 61 rotate about the pivot shaft and as the movement of the two links is transmitted to the crank 69, it will be apparent that the magnitude of such movement (for any predetermined movement of the main airfoil) will decrease as the pivot shaft is moved toward the axis of the pivotal connection between the link -61 and the crank 69 and increase as the pivot airfoil.

shaft is moved away from the axis of said pivotal connection, the rate of angular movement of the torqu tube 46 being substantially the same as that of the main airfoil of the elevator when the axis of the pivot shaft 64 is aligned with the axis of the main airfoil. So long as the main airfoil remains in a zero or neutral position, adjustment of the differential mechanism will not displace the auxiliary airfoils but will condition the mechanism for some predetermined movement of the auxiliary airfoils which may be the same as, greater, or less than that of the main It will be understood, of course, that it is not necessary that the main airfoil occupy a neutral position when the control mechanism is adjusted. In such case the resultant movement of the pivot shaft 64 angularly spreads or closes the links 65 and 61, the former if the rate of movement of the auxiliary airfoils is to be increased and the latter if such movement is to be reduced. Any'adjustment of the pivot shaft 64 to move the link 65 toward radial ali nment with the link 61 causes the latter to elevate the auxiliary airfoil l9 while any adjustment of the pivot shaft to move the link 65 away from alignment with the link 61 causes the latter to lower the auxiliary airfoil, the connecting rod 10 pivoting on the pin H to permit the links 65 and 61 to separate and close in the manner described. In this connection it will be noted that for any zero, or neutral, position of the main airfoil and the auxiliary airfoils, the axes of the pivot pins 68 and 76 will be aligned with the axis of the shaft 6|, while for a setting which will prevent relative movement between the main airfoil and auxiliary airfoils the axis of the pivot shaft 64 will, as noted, he in alignment with the axis of the main airfoil.

Referring to Figure 3, it will be noted that the auxiliary airfoils l9 and 20 are trimmed as may be desired by adjusting the length of the links which connect the crank arms 42 and 45 to the arms of the respective auxiliary airfoils. Hence any automatic control of the auxiliary airfoils in response to the movement of the main airfoil will be imposed on, or added to, such trimming adjustment. The trim setting will, therefore, be maintained for all positions of the main airfoil.

The control mechanism described has the advantage that it is positive and dependable in operation and is operative to eifect any desired differential movement between the main airfoil and the auxiliary airfoils, or to cause the main airfoil and auxiliary airfoils to move at the same rate without relative angular displacement between them. In this connection it will be understood, of course, that, although the differential control mechanism is illustrated and described in connection with the nose elevator of a particular type of airplane, this is for purposes of illustration only. The features of the invention may also be availed of to equal advantage in connection with the control surfaces, not necessarily elevators, of other types of airplanes, the control mechanism being adaptable to any control surface having main and auxiliary airfoils and wherein it is desired that the auxiliary airfoil, or airfoils, at certain times, move at a different rate than the main airfoil.

We claim as our invention:

1. Mechanism responsive to the movement of the main airfoil of a control surface also having an auxiliar airfoil, said mechanism being adapted to control relative movement between said main and auxiliary airfoils and including a pivot,

cooperating links which are pivotally connected together at one end and 1 one :or which is pivotally connected at Ethe -opposite end to saidpivot and the other of 'which is connected at the opposite end to said auxiliar airfoil, means connecting said main "airfoil to said links, whereby the movement of said main airfoil is transmitted to said auxiliaryairfoilyand means for pivotally adjusting the position of said pivot to vary the response of saidauxiliary airfoil with respect to a predetermined movement of said main airfoil.

2. Mechanism responsive to the movement of the main airfoil of a control surface also having an auxiliary airfoil, the main airfoil being mov- 'ableab'out a predetermined-axis, said mechanism "being adapted to control relative movement between said rnain and auxiliary airfoils and including a torque tube "which is coaxial with the axis of said 'm-ain airfoil and which is connected to said auxiliar airfoil, alink which is connected at one end to said torque tube, the other end of which is movable along a predetermined path to 'turn said torque tube and thereby move said auxiliary airfoil, means connecting said main airfoil and said other end of saidlink, whereby the movement of said main airfoil is'transmitted to said'auxiliary airfoil, and controllable means peratively connected to said other end of said link for adjusting the predetermined path of movement thereof to Vary the response of said auxiliary' airfoil with respect to'a predetermined movementof said main airfoil.

'3. Mechanism responsive to the movement of 'themain airfoil of a'control surface also having an auxiliary airfoil, the main airfoil being movable about a predetermined axis, said mechanism being adapted to control relative movement between said main and auxiliary airfoils and including a torque tube which is coaxial with the axis of said main airfoil and Which'is connected to said auxiliary airfoil, a pivot, cooperating links connectedtogether at one end, the other end of one of said links being connected to said torque tube andth'e other end of the other 'ofsaid links being connected to said pivot, means connecting said links to said main airfoil, whereby when the latter is .moved it causes said links to swing about said pivot and thereby move said auxiliary airfoil, and means for adjusting the position of said pivot to vary the response of said auxiliary airfoil with respect to a predetermined movement of said main airfoil, said links being movable relatively to permit adjustment of saidlpivot for thepurpose described.

4. Mechanism :responsive to the movement of thernain airfoil of a controlisurfacealso having an auxiliaryairfoil, theme-in airfoilbeing movable abcutapredetermined axis, said mechanism being ad-apted to'control relative movement between said main and auxiliary airfoils-and including a rtorque tube'which is-coaxial withthe axis of said 'main airfoil, cranks carriedby said torque tube, means connecting one of said cranks to said auxiliary airfoiLa pivot,'cooperating links :connected'together at one end,the other end of one'of said links being connected 'tothe other of said cranks and the other end of-the other of said links being connected to said pivot, means connecting said links to said'main airfoil, where- 'by when the-latter is moved it causes said links toswing about said :pivot to rotate'sai'd torque tube and thereby'move' said auxiliary airfoil, and

means for adjustingthe position ofisaid pivot to vary the response of said auxiliar airfoil with respect to :a predetermined movement of said main airfoil, said links being :movable relatively topermit adjustment of said pivot for *the purpose described.

5. Mechanism responsive :to the movement :of

the main airfoil of a control surface also having an auxiliary airfoil, the :main airfoil being movable about a predetermined axis, said mechanism being adapted to control relative movement :be-

"tween said mainand auxiliaryl'airfoils 'anddnclud- 'ing a torque tube which is coaxial with *the axis of said main airfoil, cranks carried by-said itorque tube, 'means connecting one of said :cranks 'to said auxiliary airfoil, a pivotally mounted member, one end of which carries a pivot,cooperatin'g links *connectedtogether at one end, the other end of one of-said links :being connected t'orthe other of said cranks and the other end of the other of said links being connected =tosaid "pivot,

means connecting said links 'to said main airfoil,

whereby when the latter is tmove'd it causes said llnksto swing about sai'd'pivotxand thereby rotate said torque-tube to move said auxiliary airfoiLiand means for angularly adjusting said :member to crank means operatively connecting said main airfoil andsaid link means, whereby movement of said main airfoil istransmittedto said auxil- .iary airfoil, means for adjusting the position .of

said axis to vary the response .of said-auxiliary airfoil with respectito a predetermined movement of said main airfoil, and means independent of said last named-means for adjusting the-angular position of said auxiliary airfoil with :respect "to said main airfoil.

7. Mechanism "responsive to"the"movemen't of 'the'main airfoil of'a control'surface also :having an auxiliary airfoil, the main airfoil :being rmovable about a predetermined axls,saidimechanism being adapted to control relative movement be- "tween "said "main and auxiliary :airfoils "and including a't-orque tube which-is coaxial :with the "axis of said main airfoil and which is connected -to said auxiliary "airfoil, a pivot, linka'ge means for connecting said torque tube and said pivot and which is movable about "the latter to turn said torque tube. and thereby move said auxiliary airfoil, means-connecting sai'd main -airfoil and said linkage means, -whereby the movement of said "main airfoil is transmitted to said auxiliary airfoil, "means for adjusting the position of said -pivot' to vary the response of'said. 'auxiliary airfoil'withrespecti-rto a predetermined movement of said main'airfoil, and 'meansindependent of said last named means for'adjusting; said: auxiliary airfoiliwith respect'ito saidimainiairfoil.

I 8. 'Mechanism iresponsive T vthe movement of the main airfoil of i a control surfaceflalsofthaving an auxiliary fairfoil; th main fallfoil being:movablesiaboutIa"predetermined: axi'snsaidtmeChariism being 1 adapted -:to control relative :movem-ent between said main and auxiliary airfoils and in-. cluding a torque tube which is coaxial with the axis of said main airfoil and which is connected to said auxiliary airfoil, a pivot, cooperating links pivotally connected together at one end, the other end of one of said links being connected to said pivot and the other end of the other of said links being connected to said torque tube, means connecting said links to said main airfoil, whereby the movement of the latter causes said links to swing about said pivot and thereby rotate said torque tube to move said auxiliary airfoil, means for adjusting the position of said pivot to vary the response of said auxiliary airfoil with respect to a predetermined movement of said main airfoil, and mean independent of said last named means for adjusting said auxiliary airfoil with respect to said main airfoil.

9. Mechanism responsive to the movement of the main airfoil of a control surface also havin auxiliary airfoils, the main airfoil bein movable about a predetermined axis, said mechanism being adapted to control relative movement between said main and auxiliary airfoils and including aligned, spaced-apart torque tubes which are coaxial with the axis of said main airfoil, first and second cranks on each of said torque tubes, means for connecting said first crank on each of said torque tubes to an auxiliary airfoil, a pivotally mounted member for providing pivots, cooperating pairs of links, the links of said pairs being pivotally connected together at one end and the other end of one link of each of said pairs being connected to one of said pivots and the other end of the other link of each of said pairs being connected to said second one of said cranks,

means connecting said main airfoil to said pairs of links, whereby when said main airfoil moves it causes said pairs of links to swing about said pivots to turn said torque tubes and thereby cause said auxiliary airfoils to move simultaneously, and means for angularly adjusting said pivotally mounted member to change the position of said pivots and thereby vary the response of said auxiliary airfoils With respect to a predetermined movement of said main airfoil, the links of each of said pairs being relatively movable to permit said member to be angularly adjusted for the purpose described.

10. Mechanism responsive to the pivotal movement of the main airfoil of a control surface also having an auxiliary airfoil, the main airfoil having a predetermined pivot axis, said mechanism being adapted to control relative movement between said main and auxiliary airfoils and including a rockable member having a pivot thereon which is movable from a position of coincidence with said pivot axis, a link mounted on said pivot, a second link connecting said first mentioned link with the main airfoil for pivoting said latter link about said pivot, means operatively interconnecting the auxiliary airfoil with said first mentioned link whereby said auxiliary airfoil is moved in response to movement of the main airfoil, and means for rocking said rockable member to control the relative movement between the main and auxiliary airfoils by moving said pivot from its position of coincidence with said pivot axis.

JOHN NOYES, JR. MYRON L. DAGGE'I'I', JR. 

